1. Field of the Invention
The present invention relates to a thin film transistor (TFT) including an active layer made of an oxide conductor or silicon (Si), and a display including the thin film transistor.
2. Description of the Related Art
Thin film transistors have been widely applied as fundamental technology for liquid crystal displays or organic EL (Electro Luminescence) displays. As a typical semiconductor film which is an active layer for the displays, a silicon (Si) film in a noncrystalline state (a so-called amorphous silicon film) or a polysilicon film crystallized by an excimer laser or solid-phase growth is used. Moreover, in recent years, it has been proposed that as a semiconductor film, a metal oxide capable of being formed by a low-cost apparatus such as a sputtering method is used.
In most of thin film transistors using a silicon film for an active layer, a light-shielding film is arranged to prevent light from entering the silicon film. Moreover, it has been known that in a metal oxide semiconductor, a change in electrical conductance occurs due to photoinduction (for example, refer to Japanese Unexamined Patent Application Publication No. 2007-115902 (FIG. 8)), so it has been proposed to arrange a light-shielding film.